Proper Punctuation: Apostrophes

How to Use Apostrophes

Apostrophes are used for two main purposes: to stand in the place of missing letters and to show possession.

It is rare to see a mistake when an apostrophe is used for the first of these two purposes. Words such as can’t, won’t, and shouldn’t are almost always used correctly by writers. However, when using apostrophes to show possession, some writers do make common mistakes.

This article will help you ensure you are using apostrophes correctly in your writing and will also help you avoid misusing apostrophes.

Using apostrophes to indicate possession

Usually, using an apostrophe to indicate possession is straightforward. Phrases like the woman’s blouse and Jeff’s house come up all the time. Certain words can make writers second guess whether an apostrophe should be used, though.

When the noun ends in an ‘s”

Words that end with an ‘s’ can be confusing in this regard. Is it Charles’ or Charles’s? Is it boys’ or boys’s?

The rule is quite simple. If the word is singular, you should add –‘s. If the word is plural, you should add only the apostrophe.

Correct: This is Charles’s car.

Incorrect: This is Charles’ car.

Correct: This is the boys’ room.

Incorrect: This is the boys’s room.

Note that not all plural words take their possessive forms this way. Plural words that do not end in an ‘s’ take the standard –‘s ending to become possessive.

Correct: Where are the men’s clothes?

Incorrect: Where are the mens’ clothes?

When two individuals possess something

Writers sometimes get confused when putting two entities together into the possessive form. Is it correct, for example, to write Phil and Betty’s or Phil’s and Betty’s?

Either could be correct depending on the context. If Phil and Betty own something together, Phil and Betty’s should be used. If Phil and Betty each possess their own thing, Phil’s and Betty’s should be used.

Correct: We are going to Phil and Betty’s house for dinner.

Incorrect: We are going to Phil’s and Betty’s house for dinner.

Correct: Phil’s and Betty’s houses are both in nice neighborhoods.

Incorrect: Phil and Betty’s houses are both in nice neighbourhoods.1

Common Misuses of the apostrophe

Do not use an apostrophe for non-possessive plural forms of words.

Some writers mistakenly place an apostrophe before an ‘s’ when making a non-possessive word plural.

Correct: All students must ensure they are registered for the class.

Incorrect: All student’s must ensure they are registered for the class.

More commonly, writers mistakenly place an apostrophe before an ‘s’ when writing the plural forms of numbers, abbreviations, and letters.

Correct: Personally, I think music from the 1970s is the best.

Incorrect: Personally, I think music from the 1970’s is the best.

Correct: I don’t buy DVDs anymore.

Incorrect: I don’t buy DVD’s anymore.

Correct: There were Bs written on the walls.

Incorrect: There were B’s written on the walls.

However, if the letter needs to be written in lower case, an apostrophe must be used as it otherwise looks strange. Also, any A or I must take an -‘s ending to avoid having the reader see the word as or is.

Correct: There were b’s written on the walls.

Correct: There were A’s written on the walls.

Do not use an apostrophe for possessive pronouns.

So far, we have been discussing possessive forms of nouns. Possessive forms of pronouns never take an apostrophe, though. Some possessive pronouns, such and mine do not cause any problems, but possessive pronouns that end in an ‘s’ can trick writers into improperly putting an apostrophe before the ‘s’.

Correct: This is yours now.

Incorrect: This is your’s now.

The pronoun it especially causes problems because both its and it’s are words (whereas your’s in the example above is not actually a word in the English language). It follows the same rule as other pronouns. It does not take an apostrophe to become possessive.

Correct: I have to take the dog for its walk.

Incorrect: I have to take the dog for it’s walk.

Jake Magnum, author of the Magnum Proofreading Tips blog, is dedicated to helping writers perfect their work. In addition to giving free advice on his blog, Jake helps writers by offering very affordable proofreading services at magnumproofreading.com.

1This sentence would be correct if Phil and Betty were co-owners of both houses. In the context that Phil and Betty each own their own house, this sentence is incorrect.